The present invention relates generally to elastomeric compositions having improved chemical, water and heat resistance and, specifically, to an elastomeric jacketing composition for use at elevated temperatures and under extreme pressures which can withstand exposure to oil, water and chemical environments such as are found in oil and gas wells.
Wire and cable constructions of the type employed in oil and gas wells, such as the cables running to submerged pumps, must be able to withstand exposures to pressures of 2000 psi or higher and temperatures in excess of 250.degree. F. in contact with crude oil, brines, and hot gases. Various synthetic olefin polymers have been employed in the manufacture of electric wire and cable as jacketing or insulating materials including ethylene-propylene copolymer rubbers and ethylene-propylene-diene monomer terpolymers. These materials ae useful in many applications because of their ease of compounding, good extrudability and excellent electrical characteristics. However, because these materials flow or distort at elevated temperatures and under extreme pressures and are sensitive to swelling and dissolving in various hydrocarbon solvents and oils, their use has been limited to moderate environmental conditions. Where these materials are used in the extreme environmental conditions of oil and gas wells, the materials must generally be chemically modified or protected by added layers of secondary barrier materials, with a resulting increase in manufacturing difficulty and cost.
The ethylene/acrylic elastomers have also been used in the manufacture of electrical wires and cables in the oil and gas industries. The combination of the two major monomers, ethylene and methyl acrylate, in ethylene/acrylic elastomers provides a balance of oil resistance and good heat resistance. Unfortunately, ethylene/acrylic elastomers alone are sensitive to water, aromatic hydrocarbons, and sulfide contaminants such as are often encountered in oil and gas wells.
There exists a need, therefore, for an elastomeric jacketing composition which possesses the heat and oil resistance of an ethylene/acrylic elastomer but which has improved resistance to water, aromatic hydrocarbons, and sulfide contaminants.
There exists a need for such a jacketing composition which can alleviate the need for secondary barrier materials when employed in oil and gas well wire and cable applications and which can be easily compounded and manufactured.